Preparation of biocompatible materials by immobilization of apyrase

Abstract

A prosthetic polymer material is made non-thrombogenic by immobilizing apyrase on its surface. Immobilization is preferably carried out by hydrolytically activating the surface of a polyamide polymer or a polyethylene terphthalate polymer, and treating the hydrolyzed polymer with a solution of cross-linking agent and a solution of apyrase. The apyrase converts adenosine diphosphate to adenosine monophosphate and adenosine whereby the formation of thrombi is inhibited.

We claim: 
     
       1. A method for preparing a non-thrombogenic apyrase-carrying prosthetic plastic material comprising the steps of hydrolytically activating the surface of a plastic material carrier selected from the group consisting of a polyamide polymer and a polyethylene terephthalate polymer, treating the hydrolyzed plastic carrier by immersing it into a buffered solution of a cross-linking agent selected from the group consisting of glutaraldehyde and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide and in a buffered solution of apyrase, and allowing said immersed plastic material carrier to stand for a time sufficient to effect the covalent bonding of apyrase to the surface of said plastic material carrier. 
     
     
       2. The method of claim 1 wherein said plastic material carrier is a polyamide and said hydrolysis is an acid hydrolysis. 
     
     
       3. The method of claim 1 wherein said plastic material carrier is polyethylene terephthalate, said hydrolysis is an alkaline hydrolysis, and said solution of a cross-linking agent is a buffered solution of N-ethyl-N'-(dimethylaminopropyl)carbodiimide, which solution is combined with said buffered solution of apyrase prior to the immersion therein of said hydrolytically-activated plastic material carrier. 
     
     
       4. Non-thrombogenic apyrase-carrying prosthetic plastic material articles prepared by the method of claim 1 consisting of plastic material from the group consisting of polyamides and polyethylene terephthalate having said apyrase covalently and permanently bonded on the surface thereof.